Quadruple VS
Synonym Boundary: "いち", "億", "一因", "相次いで"
All represent the core concept "one", but require precise selection.
Japanese Option A
いち
いち (ichi)
N5 / CEFR
Japanese Option B
億
おく (oku)
N3 / CEFR
Japanese Option C
一因
いちいん (ichiin)
N2 / CEFR
Japanese Option D
相次いで
あいついで (aitsuide)
N2 / CEFR
Quadruple VS Nuance Contrast & Social Differences
When expressing "one" in Japanese, you must carefully distinguish between "いち", "億", "一因", "相次いで" based on context.
- いち (いち (ichi) - Level: N5): Maps to "one" and is used when Basic number for counting. Can be used as a standalone number or with various counters.
- 億 (おく (oku) - Level: N3): Maps to "one hundred million (100,000,000)" and is used when A large numerical unit in Japanese. 1億 = 100,000,000. Often used for large amounts of money, population, or astronomical figures..
- 一因 (いちいん (ichiin) - Level: N2): Maps to "one cause; a contributing factor" and is used when Used to indicate one of several causes or factors contributing to a situation, often a negative one..
- 相次いで (あいついで (aitsuide) - Level: N2): Maps to "one after another; in succession" and is used when Describes multiple events or incidents happening consecutively. Often used for significant or repeated occurrences..
Context for "いち"
りんごが一つあります。
There is one apple.
Context for "億"
日本の人口は約1億2千万です。
Japan's population is approximately 120 million.
Context for "一因"
彼の失敗は準備不足が一因だ。
His failure was partly due to insufficient preparation.
Context for "相次いで"
事故が相次いで発生した。
Accidents occurred one after another.
Synonym Mastery Challenge
Which Japanese word perfectly fits this blank space?
Fill in the blank: "りんごが一つあります。" (Meaning: "There is one apple.")
🎉 Correct Answer!
Remember: "いち" is correct here because it represents "one" in the context: "There is one apple.".